Rough analysis of map file

https://blog.csdn.net/weixin_30632899/article/details/94867874
Map The document is MCU programmatic Map（ Map ）.

The code we wrote , After compiling and linking a series of actions , Will generate a elf File format , From this elf The file can generate a hex perhaps bin file , For burning MCU Inside to run , meanwhile （ Configurable ） Generate a program called Map The file of .

This elf The file actually contains all kinds of information about the program , Include function name 、 Variable name , Address 、 Size and other very rich information . And this map The file is from elf Propose to get , Very intuitively （ In text form ） Show which function variables are contained in each file in the program , And in which segments are these function variables allocated , What's the address , And the size of the space it occupies .

map The file contains the following ：

1. Archive member included to satisfy reference by file (symbol)
   Library function information called ： From which .a Which of them? .o
2. Allocating common symbols
   Uninitialized global variables ： size Source of variable
3. Discarded input sections
   No function is called 、 Variable
4. Memory Configuration
   according to .ld In file MEMORY To divide the memory area ： name 、 Initial address 、 length
5. Linker script and memory map
   What is needed for the link .o .a
   according to .ld In file SECTION To divide the area ：
   .txt Code segment
   .rodata Strings and local variables
   .srodata Used in the library rodata
   .rela.dyn
   .rela.text. Function information to be relocated
   .data Data segment ( Big )
   .sdata Data segment （ Small ）
   .bss Initialize to 0 The variable of ( Big )
   .sbss Initialize to 0 The variable of （ Small ）
   COMMON Uninitialized variables
   .attributes
   .debug_info
   .debug_abbrev
   .debug_loc
   .debug_aranges
   .debug_line
   .debug_str
   .debug_frame